A=(3/429-1/1.3).(3/429-1/3.5).(3/429-1/5.7)...(3/429-1/121.123)
tính A= \(\left(\frac{3}{429}-\frac{1}{1.3}\right).\left(\frac{3}{429}-\frac{1}{3.5}\right)..........\left(\frac{3}{429}-\frac{1}{121.123}\right)\)
\(\left(\frac{3}{429}-\frac{1}{1.3}\right)\left(\frac{3}{429}-\frac{1}{3.5}\right)....\left(\frac{3}{429}-\frac{1}{119.121}\right)\left(\frac{3}{429}-\frac{1}{121.123}\right)\)= ?
(\(\frac{3}{429}\)-\(\frac{1}{1.3}\)).(\(\frac{3}{429}\)-\(\frac{1}{3.5}\)).......(\(\frac{3}{429}\)-\(\frac{1}{119.121}\)).(\(\frac{3}{429}\)-\(\frac{1}{121.123}\)) Tính tích
Tính B= \(\left(\frac{3}{429}-\frac{1}{1.3}\right)\left(\frac{3}{429}-\frac{1}{3.5}\right)....\left(\frac{3}{429}-\frac{1}{119.121}\right)\left(\frac{3}{429}-\frac{1}{121.123}\right)\)
Tính C= \(\frac{1}{5.6}+\frac{1}{10.9}+\frac{1}{15.12}+...+\frac{1}{3350.2013}\)
\(\frac{1}{1.2}+\frac{1}{3.4}+\frac{1}{5.6}+...+\frac{1}{49.50}=\frac{1}{26}+\frac{1}{27}+...+\frac{1}{50}\)
b. \(\frac{1}{4}+\frac{1}{16}+\frac{1}{36}+...+\frac{1}{196}<2\)
tính tích\(\left(\frac{3}{429}-\frac{1}{1.3}\right).\left(\frac{3}{429}+\frac{1}{3.5}\right).........\left(\frac{3}{429}-\frac{1}{119.121}\right)+\left(\frac{3}{429}-\frac{1}{121.123}\right)\)
1) Chứng minh rằng với mọi số nguyên n thì phân số 3n+7 / 4n+9 là phân số tối giản
2) Tính (5/6 + 19/20 + 41/42 + 71/72 + 109/110 ) - (3/2 +13/12 + 31/30 + 57/56 + 91/90 )
3) tính ( 3/429 -1/1.3 ) (3/429 - 1/3.5 ) ( 3/429 - 1/5.7 ) ( 3/429 - 1/99.101 )
Tính tích:
\(A=\left(\frac{3}{429}-\frac{1}{1\times3}\right)\times\left(\frac{3}{429}-\frac{1}{3\times5}\right)\times...\times\left(\frac{3}{429}-\frac{1}{119\times121}\right)\times\left(\frac{1}{429}-\frac{2}{121\times123}\right)\)
A=(3/429-1/1*3)*(3/429-1/3*5)*...*(3/429-1/121*123) = ?
